1. Field of the Invention
The present invention relates to an evaluation apparatus and a method thereof for obtaining an evaluation value of a signal read from an optical recording medium, on which signal reading is performed by application of light. The present invention further relates to a program to be executed by a signal processing apparatus to realize the evaluation apparatus and the evaluation method of the present invention.
2. Description of the Related Art
In the past, the quality evaluation of an optical disc recording medium (hereinafter referred to simply as the optical disc), such as a CD (Compact Disc), a DVD (Digital Versatile Disc), and a BD (Blu-ray Disc: a registered trademark), for example, has been performed with the use of an indicator called jitter which represents in the standard deviation value the variation of edge positions of pits formed on the optical disc. Specifically, a frequency distribution table is generated on the basis of the result of detection of a plurality of edge positions of a signal read from the optical disc, and the standard deviation value of the edge positions is calculated on the basis of the frequency distribution table. An increase in the thus calculated jitter value means an increase in the variation of the edge positions. Conversely, a reduction in the jitter value means a reduction in the variation of the edge positions. That is, if an optical disc has a smaller jitter value, the optical disc can be determined to be a more favorable optical disc having less variation of the edge positions.
The related art includes Japanese Unexamined Patent Application Publication No. 2006-344338.